package com.xipin.est.utils.security;

import java.security.MessageDigest;

public final class SHA1 {

		private static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4',
				'5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

		/**
		 * Takes the raw bytes from the digest and formats them correct.
		 * 
		 * @param bytes
		 *            the raw bytes from the digest.
		 * @return the formatted bytes.
		 */
		private static String getFormattedText(byte[] bytes) {
			int len = bytes.length;
			StringBuilder buf = new StringBuilder(len * 2);
			// 把密文转换成十六进制的字符串形式
			for (int j = 0; j < len; j++) {
				buf.append(HEX_DIGITS[(bytes[j] >> 4) & 0x0f]);
				buf.append(HEX_DIGITS[bytes[j] & 0x0f]);
			}
			return buf.toString();
		}

		public static String encode(String str) {
			if (str == null) {
				return null;
			}
			try {
				MessageDigest messageDigest = MessageDigest.getInstance("SHA1");
				messageDigest.update(str.getBytes());
				return getFormattedText(messageDigest.digest());
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		}
	}
